thanks all i have been struggling with an issue..as a friend was helping me partition a hard drive on my comp he deleted my entire ubuntu operating system which held my qt wallet..i never backed up my wallet.dat equivalent on linux and i always thought wallet passphrase was == priv key...in an attempt to recover my coins i tried importing them to blockchain.infos wallet however i noticed that when i input "wallet passphrase" in the import priv key option it kept saying unknown formatt ...so with the recent light shed on the diff between priv key and wallet passphrase..i can come to a conclusion that my bitcoin are lost forever? 
thank you all again in advance for your input and help..
You could try to recover your private keys from the formatted disk. As long as the wallet.dat has not been written over there's a chance for it to work. You just need a recovery tool, and hope for the best. There's a high risk that it doesn't work though. But it could be worth a shot if you had much money in it. thank you all again in advance for your input and help..
